This invention relates to a fixed magnetic disk apparatus, and more particularly to a CSS-type (contact start/stop) disk apparatus in which positional information which is recorded on the disk is not injured by contact between the magnetic head and the magnetic disk of the apparatus.
A CSS-type fixed magnetic disk apparatus is one which has a magnetic head which is in contact with the surface of a magnetic disk when the magnetic disk is stationary or being started or stopped, and which during normal operation floats above the surface of the disk. The disk has an annular data zone formed thereon, and on either the inside or the outside of the data zone, a special annular region called a landing zone is provided on the surface of the disk for the magnetic head to contact during starting and stopping. It is conventional to record positional information on the landing zone, the information being used to position the magnetic head. However, over a period of time, the contact between the magnetic head and the landing zone during starting and stopping produces scratches on the surface of the landing zone, and these scratches can result in the deterioration of the positional information recorded thereon, making the disk apparatus inoperable.
In order to protect the positional information recorded on a landing zone, Japanese Laid-Open Utility Model Application No. 56-77027 (1981) discloses a magnetic disk having an extremely thin film (approximately 1 micron thick) of a hard magnetic material formed atop the landing zone of the disk. The thin film protects the surface of the landing zone so that even though the surface of the film may become scratched by contact with a magnetic head, the landing zone itself and the information recorded thereon remain intact. However, in accordance with that invention, it is necessary to form a shallow ledge in the surface of the disk on which to apply the film. The process of cutting the ledge and the application of the film increase the manufacturing costs of the disk. Therefore, that invention is not a satisfactory solution to the problem of preventing scratches from causing the loss of positional information.